inside sirio's sleeve antenna

[W5LZ]

How does one 1/2 wave length radiator have gain over another 1/2 wave length radiator?

Since when does an impedance matching device provide "gain"?

That '2 dBd' figure is remarkably near the difference of an isotropic gain figure and 'real world' gain figures for a 1/2 wave length radiators. Odd, ain't it?

As that little sweet thing used to say, "Where's the beef?"...
- 'Doc

 

[Marconi]

Bob or SW, does the brass rod in this image look to terminate just before the left hand margin? If so, do you have any idea what the length is, or do you think it might be near a 1/4 wave in length. From the pictures on Siro's site this whole bottom section, with the large tubing, looks to be about 1/4 of the antenna's 3/4 wavelength.

Just curious!

 

[bob85]

eddie, the gamma extends beyond the shorting clamp, i dont know how long the rod is,
the whole antenna is dc ground, the hub at the base is aluminum alloy , central monopole and sleeve are electrically connected through the hub, the so239 center conductor connects to the gamma rod ,
heres some more info on the 4mtr version.

The Four Metres Website

 

[Marconi]

eddie, the gamma extends beyond the shorting clamp, i dont know how long the rod is,
the whole antenna is dc ground, the hub at the base is aluminum alloy , central monopole and sleeve are electrically connected through the hub, the so239 center conductor connects to the gamma rod ,
heres some more info on the 4mtr version.

The Four Metres Website

Thanks Bob, now I see what you and ShockWave are saying, the rod does look to be a gamma. The sleeved CX series is similar to the Sigma4.

Thanks for the link.